In cultivation of agricultural or horticultural crops, a large number of disease-controlling agents are in use for diseases of crops. However, with conventional disease-controlling agents, there are cases that the effect of disease control is insufficient or the use of controlling agent is restricted owing to the emergence of pathogenic fungi having chemical resistance; and a considerable number of conventional disease-controlling agents are not satisfactory in that they give chemical injury or stain to plants or have toxicity to men, beasts and fishes, and give adverse effects on environment. Therefore, it is strongly desired to develop a disease-controlling agent which is low in such drawbacks and can be used safely.
In Non-Patent Literature 1 is described a 3-(pyridinylmethoxy)-1,2-benzoisothiazole compound which is similar to the present compound. However, the literature makes no description on any compound in which a substituted isothiazol-5-ylmethyl group is bonded to the 3-position of 1,2-benzoisothiazole ring via an oxygen atom, or on any agricultural or horticultural plant disease-controlling agent.
In Patent Literature 1 is described, as a specific example, a 3-(pyridin-4-ylmethoxy)-1,2-benzoisothiazole derivative which is similar to the present compound. In the literature, however, there is no description of a compound in which a substituted isothiazol-5-ylmethyl group is bonded to the 3-position of 1,2-benzoisothiazole ring via an oxygen atom. The literature further describes the 1,2-benzoisothiazole derivative as a plant disease-controlling agent, however, the disease-controlling effect thereof is not satisfactory.                Non-Patent Literature 1: Journal of the Korean Chemical Society, Vol. 41, p. 666, (1997)        Patent Literature 1: JP-A-1981-133287        